On broadband, linear-phase, flat group delay, all-pole, low-pass filters for high-speed, data communication

A tunable, 10-stage, all-pole, Papoulis, low-pass filter, occupying 0.1815 mm² is designed and integrated as a building block in a 22 nm CMOS FDSOI receiver for 5G/6G. Each filter stage comprises of a two-stage unity gain amplifier with common mode feedback loop. Tunable resistors between each stage determine the bandwidth of the filter in the range of 0.7 GHz to 1.5 GHz. An identical filter structure, but with the outputs fed back to the inputs functions as an oscillator. Correlating the oscillation frequency with the filter bandwidth, under the same tuning conditions, the filter bandwidth can be calibrated to account for PVT variations. Measurement results show an in-band OIP3 of 8.8 dBm and a nearly linear phase response at a power consumption of 35 mW to 50 mW from a 1V supply. The power/pole of 3.3 mW/GHz is the best when compared to other filters from literature.